I'm about to do some grouting. I read on the grout packet to damp cure and not having a clue what this is all about I contact the grout maker,
Morgan Ceramic Tile Adhesives, and this is what they said, "Damp curing is simply another way of saying make the grout dry slowly to ensure a great end result. When mixing and cleaning off excess grout use the minimum amount of water. Once this has been done allow to dry for 24 hours and then for a minimum of 48 hours apply water to the grout twice a day."

Just though I'd pass on this info.